Nathan Tinkler has axed three members of the Jets' coaching staff amid stand-off with the FFA.

AAP: Jane Dempster

The future of Nathan Tinkler's ownership of the Newcastle Knights NRL club is even more uncertain, with administrators moving to sell more of his assets.

Westpac Bank, one of Tinkler's major financiers, has appointed external administrators at two of Tinkler companies in the past 24 hours.

Merewether Investments Pty Ltd and Oceltip Pty Ltd have both been the subject of action by the bank and is likely to impact on Tinkler's ability to finance a bank guarantee to meet his Knights ownership obligations.

The bank guarantee, which has to be amended each year to take into account the increase in the CPI, was part of mining magnate Tinkler's deal to purchase the Knights in 2011.

I was always hopeful that a new bank guarantee could be put in place but the longer things were going along without one, the more concerned I have become.

Newcastle Knights members club chairman Nick Dan.

The appointment of external administrators at the two companies is seen as a major hurdle for Tinkler, who needs to have a $10.52 million bank guarantee in place by the end of March.

Newcastle Knights members club chairman Nick Dan says the developments are worrying.

"I was always hopeful that a new bank guarantee could be put in place but the longer things were going along without one, the more concerned I have become," he said.

"Quite concerning from the members club point of view, external administrators appointed and appears to be appointed by Westpac, who has funded the bank guarantee."

But Newcastle Knights prop Willie Mason has scoffed at reports players are not being paid on time.

Fairfax has reported some staff and player payments were not made on time this month.

I'm not really sure what's going on off the field, but I know that [Tinkler] owns the club and I'm pretty sure he'll own it for many more years.

Willie Mason

Mason insists the players are not concerned by the reports and says he does not believe Tinkler's ownership is in doubt.

"I don't think anyone thinks about it," Mason said.

"Everybody at this club has all the faith in Nathan. He communicates with the players and with the coach and through the CEO and all that kind of stuff so everybody gets paid.

"I'm not sure where the little whispers are coming from. It's always like that when you lose, everyone tries to bring up crap.